IMKO SONO-VARIO LD, User Manual

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1.2. Mode of Operation
1.2.1. Measurement value collection with pre-check, average value and filtering
SONO probes measure internally at very high cycle rates of 10 kHz and update the measurement
value at a cycle time of 250 milliseconds at the analogue output. In these 250 milliseconds a probe-
internal pre-check of the moisture values is already carried out, i.e. only plausible and physically
checked and pre-averaged single measurement values are be used for the further data processing.
This increases the reliability for the recording of the measured values to a downstream control system
significantly.
In the
Measurement Mode CS (Cyclic-Successive), an average value is not accumulated and the
cycle time here is 200 milliseconds. In the Measurement Mode CA, CF, CC and CK , not the
momentarily measured individual values are directly issued, but an average value is accumulated via a
variable number of measurements in order to filter out temporary variations. These variations can be
caused by inhomogeneous moisture distribution in the material surrounding the sensor head. The
delivery scope of SONO-VARIO includes suited parameters for the averaging period and a universally
applicable filter function deployable for currently usual applications. The time for the average value
accumulation, as well as various filter functions, can be adjusted for special applications.
1.2.2. Determination of the mineral Concentration
With the radar-based TRIME measurement method, it is now possible for the first time, not only to
measure the moisture, but also to provide information regarding the conductivity, respectively the
mineral concentration or the composition of a special material. Hereby, the attenuation of the radar
pulse in the measured volume fraction of the material is determined. This novel and innovative
measurement delivers a radar-based conductance value (RbC
–
R adar- b ased- C onductivity) in dS/m
as characteristic value which is determined in dependency of the mineral concentration and is issued
as an unscaled value. The RbC-measurement range of the SONO-VARIO is 0..12dS/m
1.2.3. Temperature Measurement
A temperature sensor is installed into the SONO-VARIO which establishes the casing temperature
3mm beneath the sensor surface. The temperature can optionally be issued at the analogue output 2.
As the TRIME electronics operates with a power of approximately 1.5 W, the probe casing does
slightly heat up. A measurement of the material temperature is therefore only possible to a certain
degree. The material temperature can be determined after an external calibration and compensation of
the sensor self-heating.
1.2.4. Temperature compensation when working at high temperatures
Despite SONO probes show a generally low temperature drift, it could be necessary to compensate a
temperature drift in special applications. SONO probes offer two possibilities for temperature
compensation.
A) Temperature compensation of the internal SONO-electronic
With this method of temperature compensation, a possible temperature drift of the SONO-electronic
can be compensated. Because the SONO-electronic shows a generally low temperature drift, SONO
probes are presetted at delivery for standard ambient conditions with the parameter
TempComp =0.2.
Dependent on SONO probe type, this parameter TempComp can be adjusted for higher temperature
ranges (up to 100°C) to values up to
TempComp =0.75. But it is to consider that it is necessary to
make a Basic-Balancing of the SONO probe in air and water, if the parameter TempComp is changed
to another value as TempComp=0.2. The parameter TempComp can be changed with the software
tool SONO-CONFIG, in the menu
"Calibration " and the window " TemperatureCompensation ".